Van der Vaart – who will miss the upcoming FIFA World Cup with a calf injury – helped Hamburg narrowly avoid relegation from the Bundesliga last term.
Hamburg, who have never been relegated, beat Greuther Furth on away goals in a play-off to maintain their top-flight status.
And former Real Madrid and Tottenham midfielder Van der Vaart thinks defender Heitinga would also be a good fit in the Bundesliga.
Van der Vaart told Berlin newspaper BZ: "Should Johnny join Hertha Berlin, they would be signing a top-quality defender.
"He has picked up a lot of valuable experience in the top leagues of European football.
"In addition, he is a true leader. (He) deals exceptionally well with young players in a squad."
Heitinga, who did not make Netherlands' final World Cup squad, was released by Fulham after their Premier League relegation.
